Telephone system.



E. R. BRODTON.

TELEPHONE SYSTEM.

APPLICATION FILED JUNE 29,1908.

Patented Aug. 31, 1909.

Wihwouo UNITED STATES PATENT oEFIo EDWARD ROBERT I BRODTON, OF MOBILE,ALABAMA, ASSIG-NOR F ONE-THIRD T0 GEORGE Ha FONDE AND ONE-THIRD T0ERNEST E. WAGAR, OF MOBILE, ALABAMA.

TELEPH NE SYSTEM.

Specification of Letters Patent.

Patented Aug. 31, 1909.

Original application filed November 19, 1907, Serial No. 402,856.Divided and this application filed June 29, 1968.

Serial No. 440,899

To altwhom it may concern:

Be it known that I, EDWARD R. BRoDroN, a citizen ofthe United States,residingat Mobile, in the county of Mobile and State of Alabama, haveinvented a new and useful Telephone System, of which is a specification.

This invention has reference to improve ments in telephone systems andis designed for use more particularly in connection with a wirelessrailway signal system, for which I have filed an application in theUnited States Patent Office on November 19, 1907, under Serial No,402,856.

the following In the aforesaid application for patent,-

there is shown and described a signal system Wherem each train andpreferably the engame of the tram carries a wireless signal outfitcomprising a sending set by means of which'impulses are sent outcontinuously and automatically in the form of two or more overlappingtrains of waves preferably of ditferent characteristics. The receivingapparatus on each train and-preferably on the engine thereof is capableof responding to the propagated trains of Waves coming from a distantpoint so as to actuate certain signal devices, and ultimately, if needbe, cause the actuation of, train controlling devices so that the trainis finally brought to a standstill on entering the danger zone. Underthese circumstances the engine man is apprised by the stopping of thetrain or otherwise that there is danger ahead or behind as the case maybe, but of thecharacter of the danger he has no information. To remedythis defect the present invention comprises a telephone system operatingin con unction with the signaling system and utilizing a portion of thesignal apparatus.

In accordance with the present invention the telephone system isdesigned to be used only when the train is at a standstill and from aconsideration of the following detail The invention will be bestunderstood descriptiontaken in connection with the accompanying drawingforming a partof th s specification, in which drawing there is shown adiagram of so much of the railway signal system as is deemed necessaryfor the understanding ofthe present invention, and in conjunctiontherewith there are shown the electric circuits of the telephone systemat one end only of the complete system.

Inorder that the relation of the telephone system to the signal systemmay be fully understood the said signal system will be first brieflydescribed.

Each train carries an aerial 1 which is' preferably mounted on theengine and III the following description it will be assumed thattheentire apparatus is mounted on the engine although it is evident thatmay be mounted upon any part of the tram. Gonnected to this aerial isone side of each secondary of two Ruhmkortf coils, by suitableconductors 2 and 2 respectively, and the other sides of these twosecondaries are connected by conductors 3 ands? to a common groundconnection 5, which may be suitably connected to the engine frameandt-hus be-- ing in electrical connection with the track rails one ofwhich is indicated at 6. The Ruhmkorff coils are indicated at 7- and 8respectively and between the terminals of the secondaries of .thesecoils are located the usual spark gaps 9.

Each coil 7 and 8 is provided with a suitable rheotome 10 by means ofwhich a constant current supplied from any suitable source as by abattery 11, is converted into an intermittent or pulsatory current whichisv ultimately converted in the secondary of the coil into alternatingcurrents passing the spark gap 9 and thereby generating Hertz-l ian orether waves to be nally thrown off at the aerial 1, all in the mannercommon in the practice of wireless telegraphy. It will be.understoodthat of course the aerial oalfnot e higherabove the engine than ispermitted by bridges and tunnels or other low structures along the lineof way,but in practice this altitude is found amply suflicient for thepropagation of Hertzian Waves for a distance of several miles, which -isample for the purposes of the system of rail way signaling forming thesubject matter of the aforesaid applicatio One side of the battery 11 isconnected by conductors'12 and 13 respectively to one side of theprimary coil of each of the Ruhmkorfi coils. The other side of thebattery 11 is connected by a conductor 14 to one side of a switch 15which in the drawing is shown of the ordinary plug or Jack type.- Theother side of the switch 15 is connected by a conductor 16 to a springarm 17 mounted onbut insulated from the casing of an electric motor 18of any suitable type. The'motor 18 is driven by a battery 19 or othersuitable source of current connected on one side to one terminal of the-motor by a conductor 20, and on theother side by a conductor 21 to abrush 22 in the path of the movable member 23 of the switch 15. When theswitch 15 is closed the circuit is completed from the brush 22 to aconductor 24 leading to the other terminal of the motor 18- andincluding a first coil is still active.

cession simple switch 25.

The motor drives a cam disk 26 in the path of which is a spring finger27 adapted to'make contact with the finger 17 to move the same for adistance. In the path of the finger 17 is another spring finger 28adapted to be ultimately engaged by the finger 17 when the latter ismoved by the finger 27 under the action of the cam disk 28.

The spring finger 27 is connectedby a conductor 29 to the other.terminal of the primary Winding of'the coil 8 and the spring finger 28is connected by a conductor 30 to the other terminal of the primarywinding of the coil. 7. I

The motor 18 is under the controLoi a suitable governor 31 by means ofwhich its speed may be fixed and maintained indefinitely.

In the primarycircuit of each coil 7 and 8 there is included a rheostat32.

in the operation of the system, the motor 18 is assumed to be constantlyrunning and at a regular interval causes a closure of the primarycircuit of the coils 7 and 8 in sucthrough the contact fingers 17, 27and 28, the arrangement being such that one coil has its primary circuitclosed before the second coil, and the second coil has its pri-- marycircuit opened before the opening of the first named coil. The resultis, that I there issent from the aeriala train ofwaves corresponding tothe first named coil, and while this train of waves is being propagatedthe circuit through the primary Winding of the second coil isestablished, and another train of vaves is propagated while the Thecircuit of the second coil is broken prior to ,the breaking of thecircuit of the first coil, as the cam disk 26 passes out of active engaement with the sprin fin er 27. The secon train of waves is .t than thefirst train of waves, but is active erei ore of shorter duration duringwaves, being overlapped on each end by the first train of waves.

. On each engine there are two or more receiving elements correspondingin number and adjustment to the number of sending coils in the sendingsystem. Each receiver includes a suitable coherer 33 included in aconductor 34 comin from the aerial '1 and ultimately grounde through therail 6 and conductor 5. suitable resistance or rheostat 35 for thepurpose of adjusting the receiver circuit to the character of thepropagated waves.

The local circuit of the coherer 33 may be traced by the conductor 36 tothe spring arm 27, through the frame-work of the structures driven bythe conductors 37 to a battery 38, and from the battery 38 by aconductor 39 to the relay magnet 40, and back to the other-side of theeoheren. The relay 40 controls another cir- Each conductor 34 includes athe activity of the first train of a motor 18 and then by 1 cuit chargedby a battery 41 and this circuit may be traced as follows. From thebattery 41 the circuit 'is by the conduetm' 42, dihrough a lamp 43 orother suitable indieating device to one terminal of the relay, thence toa 'bell 44 or other suitable signal preferably an audible signal, thencethrough an indicator 4.5, through electromagnets 46 and finallyreturning to the battery 41. In opperative relation to the magnets 45 isan armature 47 arranged to make contact with a circuit terminal 48 inits path as it moves toward the magnet 45. The armature 47 and contactterminal 48 are included in the local circuit of another coherer 4t),and this circuit may be traced from its charging battery 50 throughrelay magnets 51, then through the coherer and by a conductor 56 to thearmature 47, and the circuit is completed from the contact terminal 48to the battery 50 bythe conductor 52. The relay 51 controls a circuitcharged by a battery or other source of current indicated at 53, andthis circuit includes a lamp 54 or other suitable visual signal and abell 55 or other suitable audible signal. The'coherer 49 is included inthe aerial circuit by a conductor 56 and with the ground conductor 5 byanother conductor 57. The receiving circuit is designed also to includecertain train operating devices which however form no part of thepresentinvention and are not shown in the drawing. It maybe statedhowever, that the train controlling devices are designed to operatesubsequent to the operation of the visual and audible signals so that ifthese. last named signals be ignored by the engine man, then the trainon entering a danger zone will be automatically brought to a standstill.The receiving apparatus is so dosi ned that the first of a series oftrain waves If now it be assumed that a train has ena staudstilh theengine man will be aware of the fact that there is danger WllI-lllll apredetermined distance of his train, but will be unaware of thedangerous condition. To enable the engine man or other authorized.person to connnunicatewith the point of danger there is provided atelephone system which forms the subject matter J of the presentinvention.

In-the drawing there is indicated a tele-.

phone transmitter 57 and a telephone receiver 58, and the ordinarytelephone receiver hook is indicated at 59. phone hook 59 controls twocircuit terminals (50 and G1. The terminal 60 is connected by aconductor (32 to the conductor let bet-ween the battery 11 and theswitch 15. The terminal 61 is connected to one side of the transmitter57. The other side of the transmitter is connected by a conductor 63 toa terminal tit in the path of a switch 65 carried by the receiver 58within easy reach of the hand of the operator, and this switch 65 isconnected by a conductor 66 to the conductor 5 in oilcuit with the railsii. The switch 65 is connected to one side of the receiver 58 while theother-side of the receiver coil is con nected by a conductor 67 tothe-condifctor 30 before described, and this same side of the receiveris connected by a conductor 68 to a conductor (35) leading from andconnected to the conductor 2 before described. Leads ing from theconductrr GS) is a. conductor It) which may be a flexible conductor, sayfor instance. about 200 ft. in length and at the end of this conductorthere is a ground stake 71, adapted to be driven into the ground at aconsiderable distance from the track 6. When the coils 7 and 8 are usedwith rheotoines 10 then it is necessary in order to re duce the spark tointroduce in the primary circuit in multiple therewith a suitablecondenser such as indicated at 72, it being understood that each coilhas its individual condenserl One of the coils 7 or 8, say the coil 7utilized as an inductorium for the telephone circuit and when thetelephone is in. use it is advisable to cut out the condenser 72, butwhen'the coil is in use and the telephone is not being used, then thecondenser 72 should remain in the circuit. For this --reason thecondenser circuit terminates at two'terminal contacts 7 3, in the pathof and adapted to be bridged by the telephone'hook 59 when the telephonereceiver is hung therefrom. Then the receiver is lifted from the -hook,then the circuit of the condenser is broken at these terminal contacts73.

Let it be assumed that the train has come to a standstill because of thepresence of some danger either ahead or behind the train,

and such dangerous condition maybe the presence of another train in thesame block The tele-- within dangerous proximity, or an open switch, oran open draw in a bridge, or a broken down bridge, or in fact anydangerous condition. Under these conditions it is not necessary that themotor 18 should c011- tinue to cause the sending out of trains of waves.The switch 25 may therefore be opened and the motor be brought to astandstill. The engine man may now cause the closure of the primarycircuit of the coil 7 by moving the spring finger 28 against thespring'finger 17. This operationis facili tated by providing the springfinger .28 with a suitable manipulating button 73. By press ingdown uponthe button 73 to bring the finger 28 into contact with the finger 17 andthe latter ultimately in contact with the finger 27, trains of waves maybe propagated in accordance with some recognized code signal system, andthe receiving devices within range of sending stations will thereby benotified that at some distant point an operator wishes to talk over thetelephone vstci11. Then at eachend the receiver 58 is lifted. from thehook 5%), thus cutting out.

.the condenser 72 of a respective coal 7 orS and cutting in thetransmitter 57. 'In the meantime the engine man on the stalled train hasinserted the stake 71. at an appropriate distance from the track (3 andafter receiving the appropriate signal the operator at the other endwill do likewise.

Now "at the tr: i ismitting end the operator closes the switch. (35 thuscompleting the transmitting circuit, which may be traced from thebattery 11 through the conductor (12 to the terminal (30, sent by wayotthc book 55) to the terminal (31, and to the transmitter element 57,thence by the conductor 3 and switch (35 to the receiver, and throughthe latter by the conductor (37 to the conductor 30, and primary coil ofthe Ruhlnkorli' coil 7, returningby way of the conductor '13 to theother side' of; the battery 11. Now by talking into the transmitter 57electrical impulses are generated in the primary cirruit thus traced,and those are converted into high tension electrical impulses in thesecondary coil of the Ruhmkorfi' coil 7. The terminals of the secondarywinding of this coil are connected on one side by the conductor 3, tothe conductor 5 and ultimately to the rail 6, and on the other side bythe conductor 2 and conductor (39 to the con ductor and stake 71, whichlatter is inserted in the ground at a'considerable distance from the,rails 6, say one or' two hundred feet." During transmission thereceiving end of the line is established through the receiver 58 at thatend of the line by having the switch (35 open, when the recei\-'er isincluded in a circuit. from the rails (3 through the conductor 5 andconductor (37 to one. side of the receiver, and from the other side ofthe receiver through the conductor (38 to the conductor 70 and stake 71.When it is desired to reply over the same circuit, the receiving circuitis made a transmitting circult by closing thesw'itch 65 and thetransmrttlngclrcuit is made a receiving circuit by opening the switch 65at the correspond has demonstrated that'conversation may be carried onin this manner over a distance of two or more miles, which distance isample for the stoppageof even high speed trains before coming into closeproximity to a dangerous condition.

The Ruhmkorfi coil 7 or 8 as the case may be, operates after the mannerof an'ordinary telephone coil, when connected up as described with the.transmitter of the engine carried telephone set, but because of thelarge size of the coil, and the conditions under which it is operated,it acts with much greater vigor than the ordinary telephone coil. i

The invention'has been described as being used in connection with awireless propagating system in which Ruhmkorii'coils supplied withployed. Eyperience has taught, however, that rheotonies are troublesomeadjuncts in systems of this character. i ret'erable that the primesource of current for the Buhmkorfi' coils 7 and 8 should be analternating current generator, in which case the rheotomes becomeunnecessary and the condensers are omitted. But the battery ll is'stillretained for the primary circuit of the transmitter element. All theother circuits remain as described. I

This application a division of the aforesaitl application tiled November19, 1907, Serial Number 402,856.

What is claimed is:

1. In a systm of the character described, for transmitting trains ofwaves, said means including an induction coil, and a telephone circuithaving a transmitter capable of inclusion in the primary winding of theinduction'coil, and a receiver connected to the ground wire of theaerial transmitting system, and provided with a supplemental" groundconnection capable of being grounded at .a distance from the aerialground. k

2. In a system of the character described, means for propagating trainsof-waves including an induction coil, ,means for receivmg trains ofwaves and including signals actuated by the effect of said waves, and atelephone transmitting and receiving system including the said inductioncoil, and means for grounding two sides of the same at two points spacedapart.

3. In a system of the character described, a means for propagatingtrains of waves,

the ordinary rheotomes are emiv r an h ving a It is therefore said meansincluding a Ruhmkorfi coil, receivefs responsive to the trains of wavesand including signal devices responsive to the 510- a telephone tion ofsaid trains of waves, transmitter inc-ludable in the primary winding ofthe Ruhmkorii coil, a ground connection for the aerial side of theRuhmkorflt' coil capable of being placed at a distance from the normalground connection of the coil, and a receiver bridged across said groundconnection.

described,

4. Ina system of the character a means for propagating trains of waves,said means including a Ruhmkorfi coil, receivers responsive to'thetrains of waves, and including signal devices responsive to the actionof said trains of waves, a telephone transmitter, means for includingthe transmitter in the primary winding of the Ruhmkorfi' coil at will, aground connection for the aerial side of the Ruhmkorfi coil capable ofbeing placed at a distance from the normal ground connection of thecoil, and a receiver bridged across the said ground connections.

5. In a railway telephone system, a telephone set including atransmitter and reground connection to the track rails, and anotherground connection capable of being placed a distance from the track butstill in the vicinity of the telephone set.

6. In a telephone system, portable tele phone stations: each including atransmitting element and a receiving element, a con stant groundconnection for one side of the receiver and a removable groundconnection for the other side of the receiver constantly connected withsaid receiver and capable of being placed at a distance from the firstnamed ground connection.

in a railway telephone system, a telephone set carried by a train, aground connection for one side .oi the receiver of the system throughthe traffic rails of the railway, a'nd a removable ground connection forthe other side of the receiver also carried by the'train carrying thetelephone set and capable'ot being inserted in the ground at a -distancefrom the traliic rails.

8. In a railway telephone system, a receiver element grounded on oneside through the traffic rails, and means for grounding the other sideof the receiver comprising a suitable conductor and a terminal stakecarried therebyand insertiblein the ground at a distance from thetraific rails.

removable In testimony that I claim the foregoing as my own, I-havehereto aiiixed my signature in the presence or" two witnesses.

EDWARD ROBERT BRODTON.

. Witnesses:

E. H. RoBnn'rsoN, D: P. Bns'rsn, Jr.

